Prospective evaluation of candidate urine and cell markers in patients with interstitial cystitis enrolled in a randomized clinical trial of Bacillus Calmette Guerin (BCG)

Abstract

We measured candidate urine biomarkers and bladder cell DNA cytometry in interstitial cystitis (IC) patients randomized to receive intravesical Bacillus Calmette Guerin (BCG) or placebo in a multicenter trial. Participants received 6 weekly instillations and were followed for 34 weeks. Urine was collected at baseline, prior to fourth treatment, and at study end. Antiproliferative factor (APF) activity was determined by 3H-thymidine incorporation assay; heparin-binding epidermal growth factor-like growth factor (HB-EGF) and epidermal growth factor-like growth factor (EGF) levels were determined by ELISA. Cellular DNA content was measured by image analysis to determine the mean hyperdiploid fraction (HDF) of the urine cell pellet. Associations between marker levels, and treatment or symptoms, were examined. Baseline APF positivity rate and mean levels of the other biomarkers were similar to previous smaller studies. During the week 34 follow-up, mean HDF decreased (P = 0.0003) and HB-EGF increased (P < 0.0001); both correlated weakly with decreased urgency. There was no difference in any biomarker between symptom responders and non-responders, but the percentage of responders was low and not significantly different for BCG versus placebo. APF positivity, decreased HB-EGF, increased EGF, and increased HDF were confirmed at baseline in IC patients. Changes in HDF and HB-EGF levels correlated weakly with changes in urgency, but the low BCG response rate prevented identification of additional associations between biomarker changes and treatment or symptoms.